Apparatus for moulding plastic articles

ABSTRACT

The specification discloses a method of making an aperture-defining frame member, particularly a window-frame, comprising a rigid frame-shaped reinforcement made of e.g. a solid metal section embedded in synthetic resinous material. The method comprises placing the reinforcement in a mould cavity having the shape of the required frame member and locating the reinforcement in the cavity solely by engaging complementary interfitting formations on the reinforcement and on pin-like projections which extend from the cavity walls, e.g., recesses on the reinforcement engaging the ends of the projections. The longitudinal axes of all the projections are parallel to a predetermined plane and the engagement of the end of each projection with the complementary recess of the reinforcement prevents movement of the latter at least in first directions perpendicular to the plane. The projections are located around the reinforcement to prevent movement of the reinforcement in second directions parallel to the plane. The mould cavity is filled with synthetic resinous material to embed the reinforcement therein while the reinforcement is located in the cavity by the projections, and the cavity is subsequently opened and the projections withdrawn from the completed frame member which is then removed from the cavity.

This is a division of appplication Ser. No. 139,376, filed May 3, 1971,now U.S. Pat. No. 3,787,549.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to methods of, and apparatus for, makingaperture-defining frame members of the kind comprising a rigidframe-shaped reinforcement embedded in synthetic resinous material.

The invention has been developed in connection with the manufacture ofwindow frames and in particular the type of window frame including anouter frame to be secured to a building and an inner frame pivotally orotherwise movably mounted on the outer frame. In such window frames theouter and inner frames will normally be rectangular. The invention isnot limited to the production of such window frames and can be appliedto the manufacture of aperture-defining frame members in general. Suchframe members may be endless, e.g., rectangular or polygonal, or may beopen frame members such as, for example, a door frame which comprisestwo parallel members with a third member which joins the one ends of thetwo members while the other ends of the two parallel members areunjoined. The term "aperture-defining frame members" is used herein toinclude both open and closed frame members.

2. Description of the Prior Art

In making such frame members the synthetic resinous material, i.e.,plastics material may be injected into the mould cavity at a pressure inexcess of 10,000 p.s.i. so that the pressure in the mould cavity islikely to be at least 5,000 p.s.i. The reinforcement must be heldaccurately in position in the cavity and must also be held againstdeflection and distortion.

It has previously been proposed to hold the reinforcement either by foursets of projections lying in two planes, or sets of planes, at rightangles or by two sets of projections lying in one plane or a set ofparallel planes with metal or plastics chaplets between thereinforcement and the walls of the mould cavity. For example in theformer arrangement, considering a reinforcement of square sectionarranged with its sides vertical and horizontal there may be two sets ofprojections in vertical planes engaging horizontal surfaces of thereinforcement and two sets of projections in horizontal planes engagingvertical surfaces of the reinforcement. In the latter arrangement theremay for example be two sets of projections in vertical planes engaginghorizontal surfaces of the reinforcement and the plastics or metalchaplets may be between vertical surfaces of the reinforcement and thesides of the mould cavity.

SUMMARY OF THE INVENTION

It is an object of one aspect of the present invention to provide animproved method of making an aperture-defining frame member.

According to this aspect of the invention we provide a method of makingan aperture-defining frame member comprising a rigid frame-shapedreinforcement embedded in synthetic resinous material, the methodcomprising placing the reinforcement in a mould cavity having the shapeof the required frame member, locating the reinforcement in the cavitysolely by engaging complementary interfitting formations on thereinforcement and on pin-like projections which extend from the cavitywalls so that the longitudinal axes of all the projections are parallelto a predetermined plane and so that the engagement of said formation ofeach projection with the complementary formation of the reinforcementprevents movement of the latter at least in first directionsperpendicular to the plane, preventing movement of the reinforcement insecond directions parallel to the plane by suitable location of theprojections around the reinforcement, filling the mould cavity withsynthetic resinous material to embed the reinforcement therein while thereinforcement is located in the cavity by the projections, subsequentlyopening the cavity and withdrawing the projections from the completedframe member and then removing the latter from the cavity.

This method has the advantage over the first prior methods referred toabove in that at the most two sets of projections are required whichwholly locate the reinforcement in the cavity as distinct from the foursets of projections previously required. This arrangement makes toolingmuch simpler and less expensive.

The method embodying the invention has the advantage over the second ofthe prior methods referred to above in that it is unnecessary to insertchaplets into the mould cavity to locate the reinforcement thus verymuch simplifying and speeding up the moulding procedure.

It is preferred that the formation on the reinforcement comprises recessmeans in which the free ends of the projections engage and the recessmeans can be grooves with diverging side walls and the projections canhave conical free ends closely to engage said side walls.

Movement of the reinforcement in the mould cavity in directions parallelto the plane may be prevented solely by the arrangement of theprojections. Thus if one has a closed frame reinforcement it will beapparent that by appropriate location of the projections movement of thereinforcement can be prevented. This is also true if one has an opentype reinforcement but it is within the invention to prevent movement inat least some directions parallel to the plane by interengagement of thecomplementary formations on the reinforcement and the projections, e.g.,by providing holes in the reinforcement engaged by the projections.

We have found that the reinforcement may conveniently be a solid metalsection having on opposite sides thereof grooves with diverging sidewalls but it is within the scope of the invention to use tubularreinforcements of metal or in fact rigid reinforcements of any suitablematerial such as, for example, reinforced plastics material.

It is an object of another aspect of the invention to provide improvedapparatus for making an aperture-defining frame member comprising arigid frame-shaped reinforcement embedded in synthetic resinousmaterial.

According to this aspect of the invention, apparatus for the abovepurpose comprises mould parts which define a mould cavity having theshape of the required frame member, the mould parts including a fixedinner member, outer members movable towards and away from the innermember and a closing member; a plurality of pin-like projections forlocating the reinforcement in the cavity and which extend from thecavity walls so that the longitudinal axes of all the projections areparallel to a predetermined plane, the projections being carried by theinner and outer members and being arranged around the cavity to preventmovement of the reinforcement in the cavity at least in directionsparallel to the plane; and means for projecting into and withdrawingfrom the mould cavity those projections carried by the inner member.

With this arrangement, the projections carried by the outer members maybe fixed in position relative thereto although if desired theprojections may be movable on the outer members so as to enable all theprojections to be withdrawn from the mould cavity before moulding iscompleted if this is desired.

BRIEF DESCRIPTION OF THE DRAWING

The invention will now be described in detail by way of example withreference to the manufacture of a window frame comprising inner andouter frame parts each comprising a rigid frame-shaped reinforcementembedded in synthetic resinous material. In the accompanying drawings:

FIG. 1 is an elevation of an outer window frame member, the left handpart of FIG. 1 being an elevation in the direction of the arrow A inFIG. 5 and the right hand part of FIG. 1 being an elevation in thedirection of the arrow B in FIG. 5.

FIG. 2 is an elevation similar to FIG. 1 showing the inner frame of thewindow, the left hand part of FIG. 2 being an elevation in the directionof the Arrow A in FIG. 5 and the right hand part of FIG. 2 being anelevation in the direction of arrow B in FIG. 5;

FIG. 3 is a side elevation of a hinge detail applicable to the frames ofFIGS. 1 and 2;

FIG. 4 is a section on the line 4--4 of FIG. 3;

FIG. 5 is a vertical section through a complete window embodying theouter and inner frames of FIGS. 1 and 2;

FIG. 6 is a partial plan view of apparatus embodying the invention forproducing a frame member embodying the invention;

FIG. 7 is a section on the line 7--7 of FIG. 6;

FIG. 8 is a detailed section on the line 8--8 of FIG. 6;

FIG. 9 is a detailed section showing how the reinforcement is held inthe mould cavity by the projections; and

FIG. 10 is a detailed section similar to FIG. 9 showing an alternativearrangement for holding the reinforcement in the mold cavity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1 to 5, the window frames thereshown comprises anouter frame 20 and an inner frame 21, each frame being generallyrectangular and comprising a rectangular metal reinforcement embedded ina covering of synthetic resinous, i.e., plastics material. In FIG. 5 thereinforcement for the outer frame 20 is indicated at 22 and the coveringat 23. The reinforcement for the inner frame 21 is indicated at 24 andthe covering at 25. Each reinforcement 22 and 24 is in the form of arectangular frame formed of solid metal sections which are mitred attheir ends and are welded together. The shape of the section is similarfor each frame and comprises, referring to the reinforcement 22,parallel straight sides 26, and an inner side 27 having a groove 28therein with diverging side walls 29 and an outer side 30 having agroove 31 therein with diverging side walls 32. The material of thereinforcement frame is preferably mild steel and the frame members canbe cut off from a solid drawn section, their ends mitred and weldedtogether.

The coverings 23 and 25 are formed with flanges as required.

Thus referring to FIGS. 1 and 5, the outer frame 20 is provided with acontinuous, outwardly directed, peripheral flange 33 which is arrangedto overlap the edge of an aperture 34 in a supporting wall 35. The lowerhalf of the frame is provided with an inner flange 36 which is inwardlydirected as is clear from FIGS. 1 and 5 and which has discontinuities 37to receive stays or fastener for the window and which are not shown.

The inner frame 21, referring to FIGS. 2 and 5, has a continuous,inwardly directed flange 38 on its outer surface as shown in FIG. 5 andover the upper part of a frame it has on its inner surface an inwardlydirected flange 39 provided with discontinuities 40 for window stays andfasteners, not shown.

FIGS. 3 and 4 show a detail of a hinge means which are provided on theframes 20 and 21 whereby the frames may be hinged together. FIGS. 3 and4 actually show part of the inner frame 21 and referring to thesefigures, a U-shaped metal strap 41 has its free ends 42 welded at 43 toone side 26 of the reinforcement 24 so that the limbs 44 of the strapare generally perpendicular to the side 26. The limbs 44 are providedwith aligned apertures 45 and the strap is embedded in a part 46 of thecovering 25. Received in the apertures 45 is a metal bushing 47 which isheld in position by the plastics material of the part 45. The locationof the hinge arrangement is indicated by the circle 48 in FIG. 2 and asimilar hinge arrangement is provided on the outer frame 20 so that thepivot pins may be passed through the aligned bushes such as 47 in thehinge parts thus to hinge the frame members together. In FIG. 5, theframe members are hinged about a horizontal axis. The part 46 of thecovering is produced simultaneously with the main part of the covering25 as will be described below.

Referring to FIG. 5, the window is completed by a pane of glass 49received in the inner frame 21 and held therein by a peripheral seal 50,peripheral beading 51 and a peripheral extrusion 52 secured to the innerframe and which locate the seal 50 and the beading 51. The outerperiphery of the inner frame 20 also carries, in a groove 53 a seal 54to seal with the inner periphery of the outer frame.

The manufacture of the frames will now be described in relation to FIGS.6 to 9.

Referring first to FIGS. 6 and 7 the apparatus there shown comprises alower platen 55 and an upper platen 56. The lower platen 55 carries abase member 57 which in turn carries an inner, mould-cavity-formingmember 58. The member 58 is rectangular and is made up of four elements,two of which are shown at 59 in FIG. 6, the elements meeting at a mitredcorner 60.

The mould cavity is further defined by an outer mould-cavity-formingassembly 61 which comprises four members two of which are indicated at62 in FIG. 6 and which are independently movable towards and away fromthe elements 59. When the elements 62 are in their inner positions theyare as shown in FIGS. 6 and 7 and meet at a mitred corner 63.

The mould cavity is completed by a closing member 64 which is carried bythe upper platen 56 through an upper support 65. The inner member 58,the outer assembly 61 and the closing member 64 together define, whenthe mould is closed, a mould cavity indicated at 66. This mould cavityis in the present case in the form of an endless channel of rectangularshape in plan view but it will be appreciated that the shape of thecavity would depend on the shape of the frame member to be made.

The upper support 65 carries a number of pins, one of which is indicatedat 67 which are inclined to the vertical and each of which is receivedin a bore 68 in an outer support 69 to which a member 62 is secured.When the upper platen 56 is moved upwardly in FIG. 7 the engagement ofthe pins 67 in their bores 68 results in the outer support 69 movingoutwardly as in the direction of the arrow C in FIG. 7 and thus movingoutwardly the members 62 of the assembly 61. As will be described thisopens the mould cavity and allows the frame member to be removed and theclosing member 64 is also moved upwardly with the upward movement of theupper platen 56. Each outer support has an inclined surface 70 whichengages when the mould is closed with an inclined surface 71 on awedging member 72 carried by the upper support 65 so that when the mouldis closed the outer supports 69 are held against outward movement byengagement of the inclined surfaces.

To facilitate outward movement of the outer supports with their members62 a spring arrangement is provided as shown in FIG. 8. Thus a pluralityof springs, one of which is shown at 73 are located in bores such as 74in the base member 57. Each spring 73 acts on a flange 75 of the outersupport 69 tending to force the latter outwardly.

The reinforcement such as 22 or 24 is held in the mould cavity 66 by pinlike projections mounted on the inner elements 59 and the outer members62. Referring first to the inner members 59, the projections areindicated in FIGS. 6 and 7 at 76. Each projection is formed at its innerend with a toothed rack 77 which engages with a pinion 78. The pinion 78is formed at the upper end of a shaft 79 shown in FIG. 7 mounted in abearing sleeve 80 in the base member 57. The lower end of the shaft 79is formed with a pinion 81 which is engaged by a toothed rack 82 formedat the end of a rod 83 operated by a pneumatic or hydraulic jack 84. Aswill be seen from FIG. 6, there are two rods 83 associated with eachjack 84 and operated thereby, these two rods operating two shafts 79 tooperate two adjacent projections 76. All the projections 76 are operatedin a similar manner as will be apparent from FIGS. 6 and 7, the free endof each projection being indicated at 85.

The outer members 62 also carry projections indicated at 86 and havingconical ends 87. It will be seen from FIGS. 6 and 7 that each projection86 is directly opposite to a projection 76 and the projections 76 and 86extend in opposite directions from the walls of the mould cavity. Thusthe projections are arranged in pairs, each pair comprising a projection76 and a projection 86 and the projections 76 belong to one set and theprojections 86 to another set.

The mould assembly is provided with conventional means for introducingsynthetic resinous material into the cavity, such means being indicatedgenerally at 88 and cooling water passages 89 are provided in thevarious mould parts.

The manufacture of a frame member will now be described in generalterms. A reinforcement such as 22 or 24 is first manufactured by cuttingto the desired length a solid drawn section of the shape referred toabove and mitring and welding the ends of the length to form areinforcing frame. The mould shown in FIGS. 6, 7 and 8 is opened byraising the upper platen 56 which raises the closing member 64 and movesoutwardly the outer members 61 by engagement of the pins 67 in the bores68 and the action of the springs 74 as described above. The projections76 are retracted wholly into the elements 59 by operation of thepneumatic or hydraulic jacks 84 acting through the rods 83, the rack andpinions 82 and 81, the shafts 79, the pinions 78 and the racks 77. Thereinforcing frame is then placed in the cavity and the pneumatic jacks84 are operated to project the projections 76 into the cavity so thatthe conical ends 85 thereof engage in the groove 28 in the inner wall ofthe reinforcement and the conical end closely engages the diverging sidewall 29. The mould is then closed by lowering the upper platen 56 whichhas the effect of moving inwardly the outer members 62 via the pins 67and the bores 68 and against the action of the springs 74 and clampingsaid outer members in their inner positions through engagement of theinclined surfaces 70 and 71. Simultaneously, the closing member 64 ofthe cavity comes into engagement with the inner and outer members thusto close the cavity. As the outer members 62 move inwardly theprojections 86 engage the reinforcement and the conical ends 87 of theprojections engage in the groove 31 in the outer walls of reinforcement,the conical surfaces at the ends of the projections closely engaging thediverging walls 32 of the groove 31.

The reinforcement is thus located against movement in verticaldirections in FIG. 7 by engagement of the conical ends 85 and 87 of theprojections 76 and 86 in the grooves 28 and 31. The reinforcement islocated against movement horizontally in FIG. 7 by the arrangement ofthe projections around the reinforcement and in FIGS. 1 and 2 the centrelines of the projections are indicated to illustrate how thereinforcement is held against horizontal movement.

Plastics material is now forced into the die cavity and completelyembeds the reinforcement. It also embeds the hinge strap 41 referred toabove. When the moulding is completed and the plastic material is solid,the pneumatic jacks 84 are operated to retract the projections 76 andthe cavity is opened by raising the upper platen 56 which moves theouter members 62 outwardly and thus disengages the projections 86 fromthe frame member and the latter can then be removed from the die cavityand a further moulding operation carried out with a fresh reinforcement.

The essential feature of the present invention is the location of thereinforcement in the mould cavity. In this respect reference is made toFIG. 9 which shows on a larger scale the engagement of the conical endportions 85 and 86 of the projections 76 and 86 with the diverging walls32 and 29 of the grooves 31 and 28 respectively. It will be seen thatthe conical end portions closely engage the diverging walls thuspositively preventing movement of the reinforcing core in verticaldirections in FIG. 9. It is to be noted that the longitudinal axes ofall the projections 76 and 86 are parallel to a horizontal plane in FIG.7. By having all the projections with their longitudinal axes parallelto a plane and having interfitting formations which engage withinterfitting formations on the reinforcement, i.e., the conical ends 85and 86 in the grooves 31 and 29 it is possible wholly to locate thereinforcement in the die cavity merely by the two sets of projections 76and 86. It will be appreciated that by arranging the projections 76 and86 as shown by their centre lines in FIGS. 1 and 2 movement of thereinforcement in horizontal planes in FIG. 7 is prevented and theinterfitting formations prevents movement of the reinforcement invertical planes in that figure. This arrangement very much simplifiesmoulding since it is unnecessary to provide four sets of projections,for example projections to engage the vertical sides of thereinforcements and further projections to engage the horizontal sidesthereby to locate the reinforcement wholly within the mould cavity.

As thus far described, movement of the reinforcement in the mould cavityin horizontal planes in FIG. 7 is prevented wholly by suitablearrangement of the projections 76 and 86 around the reinforcement. Suchmovement would be prevented by having a single set of projections 76 or86 but while this may be possible in some cases our experience suggeststhat to avoid distortion of the reinforcement during moulding it isnecessary to hold the reinforcement between two sets of projections soas not only to locate the reinforcement against movement in horizontalplanes in FIG. 7 but also to prevent local distortion of thereinforcement during the moulding operation.

An alternative arrangement is shown in FIG. 10 in which there are showntwo projections 90 and 91 which engage in a bore 92 in a reinforcement93. In this arrangement, it will be appreciated that since theprojections 90 and 91 are a reasonably close fit in the bore 92 theengagement of the projections in the bore will serve to prevent movementnot only in vertical directions in FIG. 10, i.e., in directionsperpendicular to the plane containing the longitudinal axes of theprojections but will also prevent movement in some horizontaldirections, i.e., in horizontal directions perpendicular to the plane ofFIG. 10. Movement of the reinforcement in horizontal directions parallelto the plane of FIG. 10 would be prevented by a suitable arrangement ofthe projections. The arrangement of FIG. 10 is not preferred because ofthe practical disadvantage of having very accurately to provide thebores 92 in the reinforcement so that these bores align with theprojections 90 and 91 when the reinforcement is in the mould. It ispreferred to use the groove arrangement of FIG. 9 since the conical endsof the projections can engage anywhere in the grooves 28 and 31 and itis not necessary to provide accurately located bores in thereinforcement.

Various modifications may be made to the method and apparatus previouslydescribed. The method has been described as including the step ofleaving the projections 76 and 86 in engagement with the reinforcementuntil the moulding has been completed so that when the frame member iswithdrawn from the mould cavity bores are left in the covering ofplastics material. These bores may be filled with plugs and bushes asdescribed in .[.our co-pending application no..]. .Iadd.U.S. Pat. No.3,725,995 which issued on Apr. 10, 1973. .Iaddend.

If desired, however, the projections may be withdrawn during themoulding step so that the voids left by the projections are filled bythe plastics material. In such a method, the reinforcement would be heldby the projections until the mould cavity was substantially full and thereinforcement therefore located by the plastics material and then theprojections would be withdrawn so that the voids would be filled. Insuch an arrangement it would be necessary to have means on the outermould parts for withdrawing the projections 86 and such means would besimilar to the means provided on the inner mould part.

In a further modification of the method, instead of using areinforcement which is solid it may be tubular and if desired the tubemay be filled with some relatively cheap material to prevent the tubecollapsing during injection of the plastics material.

It will be seen that the invention provides an improved method of, andapparatus for, manufacturing aperture-defining frame members. Theinvention has been described in particular in relation to themanufacture of closed frame members and in particular to the manufactureof window frames. However, the invention can be applied to themanufacture of open, aperture defining frame members as described at thebeginning of the specification.

I claim:
 1. Apparatus for making an aperture-defining frame member.[.comprising.]. .Iadd.including .Iaddend.a rigid frame-shapedreinforcement embedded in synthetic resinous material, the apparatuscomprising mould parts which define a mould cavity having the shape ofthe required frame member, the mould parts including a fixed innermember, outer members movable towards and away from the inner member infirst directions parallel to a fixed plane .Iadd.containing said innermember .Iaddend.and a closing member movable towards and away from.Iadd.said .Iaddend.inner and outer members in second directionsperpendicular to said plane, a plurality of pin like projections forlocating the reinforcement in the cavity, means for mounting respectivepairs of said projections on said inner and outer members around saidcavity to prevent movement of the reinforcement in the cavity at leastin directions parallel to said plane and so that the longitudinal axisof each projection is parallel to said plane and to one of said firstdirections; and positively operable means .Iadd.engaging respectiveprojections mounted on said inner member .Iaddend.for projecting intoand withdrawing from the mould cavity those respective projectionsmounted on the inner member.
 2. Apparatus according to claim 1 whereinthe longitudinal axes of all the projections lie in said plane. 3.Apparatus according to claim 1 wherein the respective projectionsmounted on the outer members are fixed in position relative thereto soas to be withdrawn from the frame member as the outer members are movedaway from the inner member.